# Data type: string, numeric, double
# Variable form: array, string, matrix
# clear memory
rm(list=ls())
############ Basic Skills ############
# Create matrix, array, string etc:
arrayA<-c(1,2,3)
arrayB<-rep(-100,3) # repeat -100 three times
stringC <- "Hello world"
matrixX <- matrix(runif(24),4,3)
matrixY <- matrix(c(1:9),3,3)
matrixX <- data.frame(Consumption=X[,1],Income= X[,2], Wealth=X[,3])
tsData <- ts(Data,start=c(1970,1),freq=4)
length(stringC)
dim(matrixX)
############ Function ############
Quadra <- function(a, b)
{
y=(a+b)^2
return (y)
}
Quadra(2,3) # gives you 25
############ for loop ############
for(i in 1:I)
{
for(j in 1:J)
{
matrixY[i,j]<- matrixX[i,j]
}
}
############ Import Data ############
# From Excel:
install.packages("gdata")
library(gdata) # load gdata package
help(read.xls) # documentation
myData = read.xls("myData.xls") # read from first sheet
# From txt:
myData <- read.table("myData.txt")